Actuating means for hydraulic motors



March 30, 1954 M. w. HUBER 2,673,521 ACTUATING MEANS FOR HYDRAULIC MOTORS Filed Nov. 5, 1951 4 Sheets-Sheet l INVENTOR. Macrhew'W. Huber BY (9&4

Aitorneys March 30, 1954 M w, HUBER ACTUATING MEANS FOR HYDRAULIC MOTORS m m m w 4 U i O m O WW 7 n A]? 9% F h w 6 H I Filed NOV. 5, 1951 Aiiorneys March 30, 1954 M. w. HUBER 2,673,521 ACTUATING MEANS FOR HYDRAULIC MOTORS Filed Nov. 5, 1951 4 Sheets-Sheet 3 INVENTOR. Matthew W. Huber Ai-l-orneys March 30, 1954 M. w. HUBER 2,673,521

ACTUATING MEANS FOR HYDRAULIC MOTORS Filed Nov. 5, 1951 4Sheets-Sheet 4 a u s N? 2 fi w A mm w m 3 u uwm fim IN V EN TOR.

3 A'l'torneys MaithewWHuber v m m m pm M mm g @m &m ANN d K A P6 I iv an m... .w m v mm V wm. 7/7/4 m om pump coincides Patented Mar. 30, 1954 ACTUATING MEANS FOR HYDRAULIC MOTORS Matthew W. Huber,

Watertown,

N. Y., assignor to The New York Air Brake Company, a corporation of New Jersey Application November 5, 1951, Serial N 0. 254,938

2 Claims.

This invention relates to actuating mean for hydraulic motors. Specifically it is concerned with an actuating means adapted for use with hydraulic motors which are operable in two phases of which the first is characterized by rapid movement against low resistance and the second by slower movement against higher resistance.

A typical example of such a motor is a hydrualic brake motor, in which the initial moveinent of the motor removes the running slack from the brake riggin and final movement sets the brakes. The invention is not limited to use with brake motors, as it will be apparent to those skilled in the art that these operational characteristics are encountered in other hydraulic systems.

The system, according to the present invention, includes a reservoir for supplying hydraulic fluid, two pumps, of different displacements and the motors actuated by the pumps. Durin the initial movement of the motors both the large and pumps are effective to deliver fluid to move the motor. In the final stages when the motors encounter high resistance to further movement, a relief valve associated with the larger pump opens to relieve pressures therein above the pressures characteristic of the system during initial movement of the motors. The secnd pump is effective during this final stage to deliver a smaller amount of fluid at higher pressure to the motors.

In the preferred embodiment the pumps take the form of single acting piston pumps, the displacement strokes of which are 180out of phase. to say, the displacement stroke of one with the suction stroke of the other. Further, in the preferred embodiment, the larger pump charges the smaller pump.

A release valve is provided whereby the motors can be released. This release valve also controls the admission and release of pressure fluid to and from a secondary motor or motors. This secondary motor is illustrated in the form of the hydraulically actuated locking device more fully described and claimed in my copending application Serial No. 328,981, filed December 31, 1952, which is a continuation-in-part of abandoned application Serial No. 254,939, filed November 5, 1951, but it may be any type of motor.

A preferred embodiment of the invention is shown in the accompanying drawings in which:

Figure 1 is an elevation partially in section, showing the complete hydraulic system.

Figure 2 is a sectional view of-the actuating device taken on line 2--2 of Figure 1.

Figure 3 is a sectional view of the actuating device taken on line 33 of Figure 2.

Figures 4, 5 and 6 are fragmentary sectional views on the line 4-4 of Figure 3, showing the three positions of the release control valve.

Refer first to Figure 1. Reference numeral 2i indicates generally the actuating device and 22 the brake motor. Referring now to Figures 2 and 3, it will be seen that the actuating device 2| comprises a housing 23 which enclose a reservoir 24 for hydraulic fluid. The reservoir 24 a filling openin closed by a screw plug 25. Reciprocable in cylindrical bores in the housing 23 are pump pistons 26 and 21. The larger of these pistons, 25, is provided with a portion 28 of reduced diameter which, together with the housing 23, defines an annular chamber 29. The chamber 29 communicates with the reservoir 24 through a port 3i. Inlet ports 32, one of which appears in Figure 2, extend through the head 33 of this piston. Flow through these ports 32 is controlled by an annular disc type valve 34 which is biased to close by a plate spring 35. The spring 35 cts against a shouldered plug 36 which is threaded into the piston head 33. A port 31 extends through the ton head 33.

her 29 and inhibits reverse flow which is caused to occur through the inlet ports 32.

The working space 4! defined by the housing 23 and pump piston 2| is in communication with working space 39 through a passage 42. A check valve 40, of spring loaded ball type, inhibits reflux flow from the working space M to the other working space 39. A discharge valve 43 controls flow from the working space 4| to a discharge chamber 44.

The pistons 26 and 21 are reciprocated by a rocker arm 45 journaled on the rock shaft 46. The shaft 46 is supported by projecting lugs 4'! provided on the housing 23. The rocker arm 45 is positively connected to the piston 26 so that it may be reciprocated when the handle 50 is operated. The other end of the rocker arm 45 bears on the piston 2?. Engagement between these parts is maintained during the suction stroke of the piston 27 by a portion of the fluid being displaced by the piston 26.

Refer now to Figures 4, 5 and 6. The discharge chamber communicates with a cylindrical bore 48 through a port The bore 48 extends to the reservoir 24 and is provided with a port 66 which communicates with passage 5!.

Flow through the bore 48 and passages 49 and 66 is controlled by a piston valve 52. The valve 52 has a head portion 53 closely fitted in the bore 48. A gasket 54 is provided to prevent axial leakage, but it may be omitted if the parts are carefully fitted. An axial port 55 extends through the piston valve 52 from the head end to transverse ports 56. Intermediate of the head portion 53 and the ports 56 is a portion of reduced diameter, thereby affording a shoulder 51. Shoulder 51 is of such a diameter that it will seal the bore 48 when the valve 52 is in the position shown in Figure 6.

Valve 52 is spring biased against a manually shiftable cam 58 which may be shifted to move the valve to the positions shown in Figures 4, 5, and 6.

Referring again to chamber 44 (see Figure 6| to the working space motor 22 by the piston 60. The passage (see Figure 4) is connected to the locking mechanism, by a line 62. 'The locking mechanism includes a ring 63 which is spring biased to a position in which it is normal to piston stem 64. A motor plunger 65 shifts the ring 63 against this spring bias when pressure is applied to the line 62. This shifting motion cants the ring 63 causing it to cramp the piston stem 64 and inhibit motion thereof.

The operation of the device will be fully understood from the following description. With the cam 58 in the position shown in Figure 4, the passage 5| and discharge chamber 44 are in open communication with the reservoir 24 thereby releasing pressure from the system. To actuate the motor '22, the cam 58 is moved to the position shown in Figure 5, thereby isolating the discharge chamber 44 vfrom the reservoir 24, the

2) is connected by a line passage 5| remaining in communication with the reservoir 24. To and fro movement of the handle causes the pump pistons 26 and 21 toreciprocate. Fluid displaced by the piston 26 flows through the passage 42 thus charging the space 4| and causing the piston 21 to move upward, as I seen in the drawings. A major portion of the fluid delivered by the pump'piston 26 is forced past the discharge valve 43 into the motor working space 59 thus moving the piston 69 outward. Piston 21 is also effective during its displacement stroke to deliver a somewhat smaller amount of fluid to the working space 59.

During the first phase of motor operation the resistance to movement of the motorpiston is During this initial phase, the running slack is taken out of the rigging (not shown). When the running slack has been taken up the resistance to movement is markedly increased, and higher pressure is needed to move the motor. At this stage in the operation of the actuating means 2|, the relief valve 38 in the piston 26 opens to relieve pressure above a predetermined maximum in the working space 39. The piston 26 is effective during this phase of operation only to supplysufiicient fluid to charge the working-space 4|.

Pump piston 21, because of its smaller area, will deliver fiuid against a higher back pressure for a given force exerted on handle 50 than will the pump piston 26. It follows therefore, that the pump piston 21 will deliver additional fluid at a lower rate but a higher pressure than is characteristic of the system during the initial phase of motor operation. As shown in the drawings, the mechanical advantage afforded by the link- Figure 1, the discharge 59 defined in the brake mitted to passage 5| causes the motor plunger 65 to cant the ring 63 thereby cramping the piston stem 64.

.The pressure on the motor, and on the locking means, if actuated, can be released by returning the piston valve 52 to the position shown in Figure 4 and thereby releasing the pressure in passage 5| and discharge chamber 44.

While the preferred embodiment of the invention has been described in detail, different embodiments of the inventive concept are contem plated. No limitation to this particular embodiment is implied except as may be stated in the appended claims.

I claim:

1. A pump comprising in combination a housing having therein two serially connected pump bores of different diameters, a reservoir, an inlet connection to the larger bore from the reservoir, and primary and secondary discharge connections communicating with the smaller of said bores; a reciprocable piston in each of said bores; a rock shaft; a rocker arm carried by said shaft,

-' said arm being connected with each piston; an

inlet valve controlling the inlet connection; a check valve inhibiting reverse fiow from the smaller bore to the larger bore; valve means ,inhibiting reverse flow from said discharge connection to said smaller bore; a three position valve; and a valve seat, therefor having ports communicating respectively with said primary discharge connection, said secondary discharge connection and said reservoir, said three position valve effective in one position to inhibit flow from both of said discharge connections to said reservoir; in a second position to establish flow between said secondary discharge connection and said reservoir, and inhibit flow from said primary discharge connection to said reservoir; and in a third position to establish flow between said reservoir and both of the discharge connections.

2. The combination defined in claim ,1 in which said rocker arm is mechanically connected to the larger piston and 'bears on the outer end of the smaller piston, the bearing between the arm and the smaller piston being maintained during its suction stroke by fluid displaced by the larger piston. I

MATTHEW W. HUBER.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Apr. 21, 1949 

